Originally Posted by gt1guy
You can always use a non-screw pin type shackle.
Once the flange on a screw pin shackle bottoms out, it can't get a whole lot tighter. Nothing a screw driver in the hole or a crescent wrench can't fix.
Rigging up anything where the screw pin would back out is a rigging 101 fail.
Something that I've noticed on some of these ring snatch blocks, is that they are very small.
The reason normal snatch blocks are the size that they are is to keep the rope in the basket rating of a load chart. When the diameter gets below a certain point.......it's considered a choker, and the load rating gets cut way down...........like in half for a strap. Reason being, is that only the fibers on the outboard side are in tension, the inboard side (touching) are bunched up and not in tension they're just along for the ride.
Has there been any actual testing to failure with a load cell on these things? Not saying the rings themselves failing, but the loads the rope will fail at.
Yes, the sailing ones are tested and have a safe working load 40-50% less than breaking strength. Working loads on these are higher than the soft shackles they are connected with.
Keep in mind that Dyneema winchline as well as other material lines are rated at average breaking strength. Strength of a soft shackle depends on the type of knot (button knot is strongest) and the bend radius of the eye. The soft shackle when tied properly is about 110% of theoretical break strength of the line. Any 20mm lead ring is going to be more than adequate for recovery operations.